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file.c

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * file.c
 *
 * File open, close, extend, truncate
 *
 * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/uio.h>
#include <linux/sched.h>
#include <linux/splice.h>
#include <linux/mount.h>
#include <linux/writeback.h>
#include <linux/falloc.h>

#define MLOG_MASK_PREFIX ML_INODE
#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "aops.h"
#include "dir.h"
#include "dlmglue.h"
#include "extent_map.h"
#include "file.h"
#include "sysfile.h"
#include "inode.h"
#include "ioctl.h"
#include "journal.h"
#include "mmap.h"
#include "suballoc.h"
#include "super.h"

#include "buffer_head_io.h"

static int ocfs2_sync_inode(struct inode *inode)
{
      filemap_fdatawrite(inode->i_mapping);
      return sync_mapping_buffers(inode->i_mapping);
}

static int ocfs2_file_open(struct inode *inode, struct file *file)
{
      int status;
      int mode = file->f_flags;
      struct ocfs2_inode_info *oi = OCFS2_I(inode);

      mlog_entry("(0x%p, 0x%p, '%.*s')\n", inode, file,
               file->f_path.dentry->d_name.len, file->f_path.dentry->d_name.name);

      spin_lock(&oi->ip_lock);

      /* Check that the inode hasn't been wiped from disk by another
       * node. If it hasn't then we're safe as long as we hold the
       * spin lock until our increment of open count. */
      if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
            spin_unlock(&oi->ip_lock);

            status = -ENOENT;
            goto leave;
      }

      if (mode & O_DIRECT)
            oi->ip_flags |= OCFS2_INODE_OPEN_DIRECT;

      oi->ip_open_count++;
      spin_unlock(&oi->ip_lock);
      status = 0;
leave:
      mlog_exit(status);
      return status;
}

static int ocfs2_file_release(struct inode *inode, struct file *file)
{
      struct ocfs2_inode_info *oi = OCFS2_I(inode);

      mlog_entry("(0x%p, 0x%p, '%.*s')\n", inode, file,
                   file->f_path.dentry->d_name.len,
                   file->f_path.dentry->d_name.name);

      spin_lock(&oi->ip_lock);
      if (!--oi->ip_open_count)
            oi->ip_flags &= ~OCFS2_INODE_OPEN_DIRECT;
      spin_unlock(&oi->ip_lock);

      mlog_exit(0);

      return 0;
}

static int ocfs2_sync_file(struct file *file,
                     struct dentry *dentry,
                     int datasync)
{
      int err = 0;
      journal_t *journal;
      struct inode *inode = dentry->d_inode;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

      mlog_entry("(0x%p, 0x%p, %d, '%.*s')\n", file, dentry, datasync,
               dentry->d_name.len, dentry->d_name.name);

      err = ocfs2_sync_inode(dentry->d_inode);
      if (err)
            goto bail;

      journal = osb->journal->j_journal;
      err = journal_force_commit(journal);

bail:
      mlog_exit(err);

      return (err < 0) ? -EIO : 0;
}

int ocfs2_should_update_atime(struct inode *inode,
                        struct vfsmount *vfsmnt)
{
      struct timespec now;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

      if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
            return 0;

      if ((inode->i_flags & S_NOATIME) ||
          ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)))
            return 0;

      /*
       * We can be called with no vfsmnt structure - NFSD will
       * sometimes do this.
       *
       * Note that our action here is different than touch_atime() -
       * if we can't tell whether this is a noatime mount, then we
       * don't know whether to trust the value of s_atime_quantum.
       */
      if (vfsmnt == NULL)
            return 0;

      if ((vfsmnt->mnt_flags & MNT_NOATIME) ||
          ((vfsmnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))
            return 0;

      if (vfsmnt->mnt_flags & MNT_RELATIME) {
            if ((timespec_compare(&inode->i_atime, &inode->i_mtime) <= 0) ||
                (timespec_compare(&inode->i_atime, &inode->i_ctime) <= 0))
                  return 1;

            return 0;
      }

      now = CURRENT_TIME;
      if ((now.tv_sec - inode->i_atime.tv_sec <= osb->s_atime_quantum))
            return 0;
      else
            return 1;
}

int ocfs2_update_inode_atime(struct inode *inode,
                       struct buffer_head *bh)
{
      int ret;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
      handle_t *handle;
      struct ocfs2_dinode *di = (struct ocfs2_dinode *) bh->b_data;

      mlog_entry_void();

      handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
      if (handle == NULL) {
            ret = -ENOMEM;
            mlog_errno(ret);
            goto out;
      }

      ret = ocfs2_journal_access(handle, inode, bh,
                           OCFS2_JOURNAL_ACCESS_WRITE);
      if (ret) {
            mlog_errno(ret);
            goto out_commit;
      }

      /*
       * Don't use ocfs2_mark_inode_dirty() here as we don't always
       * have i_mutex to guard against concurrent changes to other
       * inode fields.
       */
      inode->i_atime = CURRENT_TIME;
      di->i_atime = cpu_to_le64(inode->i_atime.tv_sec);
      di->i_atime_nsec = cpu_to_le32(inode->i_atime.tv_nsec);

      ret = ocfs2_journal_dirty(handle, bh);
      if (ret < 0)
            mlog_errno(ret);

out_commit:
      ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);
out:
      mlog_exit(ret);
      return ret;
}

static int ocfs2_set_inode_size(handle_t *handle,
                        struct inode *inode,
                        struct buffer_head *fe_bh,
                        u64 new_i_size)
{
      int status;

      mlog_entry_void();
      i_size_write(inode, new_i_size);
      inode->i_blocks = ocfs2_inode_sector_count(inode);
      inode->i_ctime = inode->i_mtime = CURRENT_TIME;

      status = ocfs2_mark_inode_dirty(handle, inode, fe_bh);
      if (status < 0) {
            mlog_errno(status);
            goto bail;
      }

bail:
      mlog_exit(status);
      return status;
}

static int ocfs2_simple_size_update(struct inode *inode,
                            struct buffer_head *di_bh,
                            u64 new_i_size)
{
      int ret;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
      handle_t *handle = NULL;

      handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
      if (handle == NULL) {
            ret = -ENOMEM;
            mlog_errno(ret);
            goto out;
      }

      ret = ocfs2_set_inode_size(handle, inode, di_bh,
                           new_i_size);
      if (ret < 0)
            mlog_errno(ret);

      ocfs2_commit_trans(osb, handle);
out:
      return ret;
}

static int ocfs2_orphan_for_truncate(struct ocfs2_super *osb,
                             struct inode *inode,
                             struct buffer_head *fe_bh,
                             u64 new_i_size)
{
      int status;
      handle_t *handle;
      struct ocfs2_dinode *di;
      u64 cluster_bytes;

      mlog_entry_void();

      /* TODO: This needs to actually orphan the inode in this
       * transaction. */

      handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
      if (IS_ERR(handle)) {
            status = PTR_ERR(handle);
            mlog_errno(status);
            goto out;
      }

      status = ocfs2_journal_access(handle, inode, fe_bh,
                              OCFS2_JOURNAL_ACCESS_WRITE);
      if (status < 0) {
            mlog_errno(status);
            goto out_commit;
      }

      /*
       * Do this before setting i_size.
       */
      cluster_bytes = ocfs2_align_bytes_to_clusters(inode->i_sb, new_i_size);
      status = ocfs2_zero_range_for_truncate(inode, handle, new_i_size,
                                     cluster_bytes);
      if (status) {
            mlog_errno(status);
            goto out_commit;
      }

      i_size_write(inode, new_i_size);
      inode->i_ctime = inode->i_mtime = CURRENT_TIME;

      di = (struct ocfs2_dinode *) fe_bh->b_data;
      di->i_size = cpu_to_le64(new_i_size);
      di->i_ctime = di->i_mtime = cpu_to_le64(inode->i_ctime.tv_sec);
      di->i_ctime_nsec = di->i_mtime_nsec = cpu_to_le32(inode->i_ctime.tv_nsec);

      status = ocfs2_journal_dirty(handle, fe_bh);
      if (status < 0)
            mlog_errno(status);

out_commit:
      ocfs2_commit_trans(osb, handle);
out:

      mlog_exit(status);
      return status;
}

static int ocfs2_truncate_file(struct inode *inode,
                         struct buffer_head *di_bh,
                         u64 new_i_size)
{
      int status = 0;
      struct ocfs2_dinode *fe = NULL;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
      struct ocfs2_truncate_context *tc = NULL;

      mlog_entry("(inode = %llu, new_i_size = %llu\n",
               (unsigned long long)OCFS2_I(inode)->ip_blkno,
               (unsigned long long)new_i_size);

      fe = (struct ocfs2_dinode *) di_bh->b_data;
      if (!OCFS2_IS_VALID_DINODE(fe)) {
            OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, fe);
            status = -EIO;
            goto bail;
      }

      mlog_bug_on_msg(le64_to_cpu(fe->i_size) != i_size_read(inode),
                  "Inode %llu, inode i_size = %lld != di "
                  "i_size = %llu, i_flags = 0x%x\n",
                  (unsigned long long)OCFS2_I(inode)->ip_blkno,
                  i_size_read(inode),
                  (unsigned long long)le64_to_cpu(fe->i_size),
                  le32_to_cpu(fe->i_flags));

      if (new_i_size > le64_to_cpu(fe->i_size)) {
            mlog(0, "asked to truncate file with size (%llu) to size (%llu)!\n",
                 (unsigned long long)le64_to_cpu(fe->i_size),
                 (unsigned long long)new_i_size);
            status = -EINVAL;
            mlog_errno(status);
            goto bail;
      }

      mlog(0, "inode %llu, i_size = %llu, new_i_size = %llu\n",
           (unsigned long long)le64_to_cpu(fe->i_blkno),
           (unsigned long long)le64_to_cpu(fe->i_size),
           (unsigned long long)new_i_size);

      /* lets handle the simple truncate cases before doing any more
       * cluster locking. */
      if (new_i_size == le64_to_cpu(fe->i_size))
            goto bail;

      down_write(&OCFS2_I(inode)->ip_alloc_sem);

      /* This forces other nodes to sync and drop their pages. Do
       * this even if we have a truncate without allocation change -
       * ocfs2 cluster sizes can be much greater than page size, so
       * we have to truncate them anyway.  */
      status = ocfs2_data_lock(inode, 1);
      if (status < 0) {
            up_write(&OCFS2_I(inode)->ip_alloc_sem);

            mlog_errno(status);
            goto bail;
      }

      unmap_mapping_range(inode->i_mapping, new_i_size + PAGE_SIZE - 1, 0, 1);
      truncate_inode_pages(inode->i_mapping, new_i_size);

      if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
            status = ocfs2_truncate_inline(inode, di_bh, new_i_size,
                                     i_size_read(inode), 1);
            if (status)
                  mlog_errno(status);

            goto bail_unlock_data;
      }

      /* alright, we're going to need to do a full blown alloc size
       * change. Orphan the inode so that recovery can complete the
       * truncate if necessary. This does the task of marking
       * i_size. */
      status = ocfs2_orphan_for_truncate(osb, inode, di_bh, new_i_size);
      if (status < 0) {
            mlog_errno(status);
            goto bail_unlock_data;
      }

      status = ocfs2_prepare_truncate(osb, inode, di_bh, &tc);
      if (status < 0) {
            mlog_errno(status);
            goto bail_unlock_data;
      }

      status = ocfs2_commit_truncate(osb, inode, di_bh, tc);
      if (status < 0) {
            mlog_errno(status);
            goto bail_unlock_data;
      }

      /* TODO: orphan dir cleanup here. */
bail_unlock_data:
      ocfs2_data_unlock(inode, 1);

      up_write(&OCFS2_I(inode)->ip_alloc_sem);

bail:

      mlog_exit(status);
      return status;
}

/*
 * extend allocation only here.
 * we'll update all the disk stuff, and oip->alloc_size
 *
 * expect stuff to be locked, a transaction started and enough data /
 * metadata reservations in the contexts.
 *
 * Will return -EAGAIN, and a reason if a restart is needed.
 * If passed in, *reason will always be set, even in error.
 */
int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
                         struct inode *inode,
                         u32 *logical_offset,
                         u32 clusters_to_add,
                         int mark_unwritten,
                         struct buffer_head *fe_bh,
                         handle_t *handle,
                         struct ocfs2_alloc_context *data_ac,
                         struct ocfs2_alloc_context *meta_ac,
                         enum ocfs2_alloc_restarted *reason_ret)
{
      int status = 0;
      int free_extents;
      struct ocfs2_dinode *fe = (struct ocfs2_dinode *) fe_bh->b_data;
      enum ocfs2_alloc_restarted reason = RESTART_NONE;
      u32 bit_off, num_bits;
      u64 block;
      u8 flags = 0;

      BUG_ON(!clusters_to_add);

      if (mark_unwritten)
            flags = OCFS2_EXT_UNWRITTEN;

      free_extents = ocfs2_num_free_extents(osb, inode, fe);
      if (free_extents < 0) {
            status = free_extents;
            mlog_errno(status);
            goto leave;
      }

      /* there are two cases which could cause us to EAGAIN in the
       * we-need-more-metadata case:
       * 1) we haven't reserved *any*
       * 2) we are so fragmented, we've needed to add metadata too
       *    many times. */
      if (!free_extents && !meta_ac) {
            mlog(0, "we haven't reserved any metadata!\n");
            status = -EAGAIN;
            reason = RESTART_META;
            goto leave;
      } else if ((!free_extents)
               && (ocfs2_alloc_context_bits_left(meta_ac)
                   < ocfs2_extend_meta_needed(fe))) {
            mlog(0, "filesystem is really fragmented...\n");
            status = -EAGAIN;
            reason = RESTART_META;
            goto leave;
      }

      status = __ocfs2_claim_clusters(osb, handle, data_ac, 1,
                              clusters_to_add, &bit_off, &num_bits);
      if (status < 0) {
            if (status != -ENOSPC)
                  mlog_errno(status);
            goto leave;
      }

      BUG_ON(num_bits > clusters_to_add);

      /* reserve our write early -- insert_extent may update the inode */
      status = ocfs2_journal_access(handle, inode, fe_bh,
                              OCFS2_JOURNAL_ACCESS_WRITE);
      if (status < 0) {
            mlog_errno(status);
            goto leave;
      }

      block = ocfs2_clusters_to_blocks(osb->sb, bit_off);
      mlog(0, "Allocating %u clusters at block %u for inode %llu\n",
           num_bits, bit_off, (unsigned long long)OCFS2_I(inode)->ip_blkno);
      status = ocfs2_insert_extent(osb, handle, inode, fe_bh,
                             *logical_offset, block, num_bits,
                             flags, meta_ac);
      if (status < 0) {
            mlog_errno(status);
            goto leave;
      }

      status = ocfs2_journal_dirty(handle, fe_bh);
      if (status < 0) {
            mlog_errno(status);
            goto leave;
      }

      clusters_to_add -= num_bits;
      *logical_offset += num_bits;

      if (clusters_to_add) {
            mlog(0, "need to alloc once more, clusters = %u, wanted = "
                 "%u\n", fe->i_clusters, clusters_to_add);
            status = -EAGAIN;
            reason = RESTART_TRANS;
      }

leave:
      mlog_exit(status);
      if (reason_ret)
            *reason_ret = reason;
      return status;
}

/*
 * For a given allocation, determine which allocators will need to be
 * accessed, and lock them, reserving the appropriate number of bits.
 *
 * Sparse file systems call this from ocfs2_write_begin_nolock()
 * and ocfs2_allocate_unwritten_extents().
 *
 * File systems which don't support holes call this from
 * ocfs2_extend_allocation().
 */
int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
                    u32 clusters_to_add, u32 extents_to_split,
                    struct ocfs2_alloc_context **data_ac,
                    struct ocfs2_alloc_context **meta_ac)
{
      int ret = 0, num_free_extents;
      unsigned int max_recs_needed = clusters_to_add + 2 * extents_to_split;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

      *meta_ac = NULL;
      if (data_ac)
            *data_ac = NULL;

      BUG_ON(clusters_to_add != 0 && data_ac == NULL);

      mlog(0, "extend inode %llu, i_size = %lld, di->i_clusters = %u, "
           "clusters_to_add = %u, extents_to_split = %u\n",
           (unsigned long long)OCFS2_I(inode)->ip_blkno, i_size_read(inode),
           le32_to_cpu(di->i_clusters), clusters_to_add, extents_to_split);

      num_free_extents = ocfs2_num_free_extents(osb, inode, di);
      if (num_free_extents < 0) {
            ret = num_free_extents;
            mlog_errno(ret);
            goto out;
      }

      /*
       * Sparse allocation file systems need to be more conservative
       * with reserving room for expansion - the actual allocation
       * happens while we've got a journal handle open so re-taking
       * a cluster lock (because we ran out of room for another
       * extent) will violate ordering rules.
       *
       * Most of the time we'll only be seeing this 1 cluster at a time
       * anyway.
       *
       * Always lock for any unwritten extents - we might want to
       * add blocks during a split.
       */
      if (!num_free_extents ||
          (ocfs2_sparse_alloc(osb) && num_free_extents < max_recs_needed)) {
            ret = ocfs2_reserve_new_metadata(osb, di, meta_ac);
            if (ret < 0) {
                  if (ret != -ENOSPC)
                        mlog_errno(ret);
                  goto out;
            }
      }

      if (clusters_to_add == 0)
            goto out;

      ret = ocfs2_reserve_clusters(osb, clusters_to_add, data_ac);
      if (ret < 0) {
            if (ret != -ENOSPC)
                  mlog_errno(ret);
            goto out;
      }

out:
      if (ret) {
            if (*meta_ac) {
                  ocfs2_free_alloc_context(*meta_ac);
                  *meta_ac = NULL;
            }

            /*
             * We cannot have an error and a non null *data_ac.
             */
      }

      return ret;
}

static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
                             u32 clusters_to_add, int mark_unwritten)
{
      int status = 0;
      int restart_func = 0;
      int credits;
      u32 prev_clusters;
      struct buffer_head *bh = NULL;
      struct ocfs2_dinode *fe = NULL;
      handle_t *handle = NULL;
      struct ocfs2_alloc_context *data_ac = NULL;
      struct ocfs2_alloc_context *meta_ac = NULL;
      enum ocfs2_alloc_restarted why;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

      mlog_entry("(clusters_to_add = %u)\n", clusters_to_add);

      /*
       * This function only exists for file systems which don't
       * support holes.
       */
      BUG_ON(mark_unwritten && !ocfs2_sparse_alloc(osb));

      status = ocfs2_read_block(osb, OCFS2_I(inode)->ip_blkno, &bh,
                          OCFS2_BH_CACHED, inode);
      if (status < 0) {
            mlog_errno(status);
            goto leave;
      }

      fe = (struct ocfs2_dinode *) bh->b_data;
      if (!OCFS2_IS_VALID_DINODE(fe)) {
            OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, fe);
            status = -EIO;
            goto leave;
      }

restart_all:
      BUG_ON(le32_to_cpu(fe->i_clusters) != OCFS2_I(inode)->ip_clusters);

      status = ocfs2_lock_allocators(inode, fe, clusters_to_add, 0, &data_ac,
                               &meta_ac);
      if (status) {
            mlog_errno(status);
            goto leave;
      }

      credits = ocfs2_calc_extend_credits(osb->sb, fe, clusters_to_add);
      handle = ocfs2_start_trans(osb, credits);
      if (IS_ERR(handle)) {
            status = PTR_ERR(handle);
            handle = NULL;
            mlog_errno(status);
            goto leave;
      }

restarted_transaction:
      /* reserve a write to the file entry early on - that we if we
       * run out of credits in the allocation path, we can still
       * update i_size. */
      status = ocfs2_journal_access(handle, inode, bh,
                              OCFS2_JOURNAL_ACCESS_WRITE);
      if (status < 0) {
            mlog_errno(status);
            goto leave;
      }

      prev_clusters = OCFS2_I(inode)->ip_clusters;

      status = ocfs2_do_extend_allocation(osb,
                                  inode,
                                  &logical_start,
                                  clusters_to_add,
                                  mark_unwritten,
                                  bh,
                                  handle,
                                  data_ac,
                                  meta_ac,
                                  &why);
      if ((status < 0) && (status != -EAGAIN)) {
            if (status != -ENOSPC)
                  mlog_errno(status);
            goto leave;
      }

      status = ocfs2_journal_dirty(handle, bh);
      if (status < 0) {
            mlog_errno(status);
            goto leave;
      }

      spin_lock(&OCFS2_I(inode)->ip_lock);
      clusters_to_add -= (OCFS2_I(inode)->ip_clusters - prev_clusters);
      spin_unlock(&OCFS2_I(inode)->ip_lock);

      if (why != RESTART_NONE && clusters_to_add) {
            if (why == RESTART_META) {
                  mlog(0, "restarting function.\n");
                  restart_func = 1;
            } else {
                  BUG_ON(why != RESTART_TRANS);

                  mlog(0, "restarting transaction.\n");
                  /* TODO: This can be more intelligent. */
                  credits = ocfs2_calc_extend_credits(osb->sb,
                                              fe,
                                              clusters_to_add);
                  status = ocfs2_extend_trans(handle, credits);
                  if (status < 0) {
                        /* handle still has to be committed at
                         * this point. */
                        status = -ENOMEM;
                        mlog_errno(status);
                        goto leave;
                  }
                  goto restarted_transaction;
            }
      }

      mlog(0, "fe: i_clusters = %u, i_size=%llu\n",
           le32_to_cpu(fe->i_clusters),
           (unsigned long long)le64_to_cpu(fe->i_size));
      mlog(0, "inode: ip_clusters=%u, i_size=%lld\n",
           OCFS2_I(inode)->ip_clusters, i_size_read(inode));

leave:
      if (handle) {
            ocfs2_commit_trans(osb, handle);
            handle = NULL;
      }
      if (data_ac) {
            ocfs2_free_alloc_context(data_ac);
            data_ac = NULL;
      }
      if (meta_ac) {
            ocfs2_free_alloc_context(meta_ac);
            meta_ac = NULL;
      }
      if ((!status) && restart_func) {
            restart_func = 0;
            goto restart_all;
      }
      if (bh) {
            brelse(bh);
            bh = NULL;
      }

      mlog_exit(status);
      return status;
}

/* Some parts of this taken from generic_cont_expand, which turned out
 * to be too fragile to do exactly what we need without us having to
 * worry about recursive locking in ->prepare_write() and
 * ->commit_write(). */
static int ocfs2_write_zero_page(struct inode *inode,
                         u64 size)
{
      struct address_space *mapping = inode->i_mapping;
      struct page *page;
      unsigned long index;
      unsigned int offset;
      handle_t *handle = NULL;
      int ret;

      offset = (size & (PAGE_CACHE_SIZE-1)); /* Within page */
      /* ugh.  in prepare/commit_write, if from==to==start of block, we 
      ** skip the prepare.  make sure we never send an offset for the start
      ** of a block
      */
      if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) {
            offset++;
      }
      index = size >> PAGE_CACHE_SHIFT;

      page = grab_cache_page(mapping, index);
      if (!page) {
            ret = -ENOMEM;
            mlog_errno(ret);
            goto out;
      }

      ret = ocfs2_prepare_write_nolock(inode, page, offset, offset);
      if (ret < 0) {
            mlog_errno(ret);
            goto out_unlock;
      }

      if (ocfs2_should_order_data(inode)) {
            handle = ocfs2_start_walk_page_trans(inode, page, offset,
                                         offset);
            if (IS_ERR(handle)) {
                  ret = PTR_ERR(handle);
                  handle = NULL;
                  goto out_unlock;
            }
      }

      /* must not update i_size! */
      ret = block_commit_write(page, offset, offset);
      if (ret < 0)
            mlog_errno(ret);
      else
            ret = 0;

      if (handle)
            ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);
out_unlock:
      unlock_page(page);
      page_cache_release(page);
out:
      return ret;
}

static int ocfs2_zero_extend(struct inode *inode,
                       u64 zero_to_size)
{
      int ret = 0;
      u64 start_off;
      struct super_block *sb = inode->i_sb;

      start_off = ocfs2_align_bytes_to_blocks(sb, i_size_read(inode));
      while (start_off < zero_to_size) {
            ret = ocfs2_write_zero_page(inode, start_off);
            if (ret < 0) {
                  mlog_errno(ret);
                  goto out;
            }

            start_off += sb->s_blocksize;

            /*
             * Very large extends have the potential to lock up
             * the cpu for extended periods of time.
             */
            cond_resched();
      }

out:
      return ret;
}

int ocfs2_extend_no_holes(struct inode *inode, u64 new_i_size, u64 zero_to)
{
      int ret;
      u32 clusters_to_add;
      struct ocfs2_inode_info *oi = OCFS2_I(inode);

      clusters_to_add = ocfs2_clusters_for_bytes(inode->i_sb, new_i_size);
      if (clusters_to_add < oi->ip_clusters)
            clusters_to_add = 0;
      else
            clusters_to_add -= oi->ip_clusters;

      if (clusters_to_add) {
            ret = __ocfs2_extend_allocation(inode, oi->ip_clusters,
                                    clusters_to_add, 0);
            if (ret) {
                  mlog_errno(ret);
                  goto out;
            }
      }

      /*
       * Call this even if we don't add any clusters to the tree. We
       * still need to zero the area between the old i_size and the
       * new i_size.
       */
      ret = ocfs2_zero_extend(inode, zero_to);
      if (ret < 0)
            mlog_errno(ret);

out:
      return ret;
}

static int ocfs2_extend_file(struct inode *inode,
                       struct buffer_head *di_bh,
                       u64 new_i_size)
{
      int ret = 0, data_locked = 0;
      struct ocfs2_inode_info *oi = OCFS2_I(inode);

      BUG_ON(!di_bh);

      /* setattr sometimes calls us like this. */
      if (new_i_size == 0)
            goto out;

      if (i_size_read(inode) == new_i_size)
            goto out;
      BUG_ON(new_i_size < i_size_read(inode));

      /*
       * Fall through for converting inline data, even if the fs
       * supports sparse files.
       *
       * The check for inline data here is legal - nobody can add
       * the feature since we have i_mutex. We must check it again
       * after acquiring ip_alloc_sem though, as paths like mmap
       * might have raced us to converting the inode to extents.
       */
      if (!(oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
          && ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
            goto out_update_size;

      /* 
       * protect the pages that ocfs2_zero_extend is going to be
       * pulling into the page cache.. we do this before the
       * metadata extend so that we don't get into the situation
       * where we've extended the metadata but can't get the data
       * lock to zero.
       */
      ret = ocfs2_data_lock(inode, 1);
      if (ret < 0) {
            mlog_errno(ret);
            goto out;
      }
      data_locked = 1;

      /*
       * The alloc sem blocks people in read/write from reading our
       * allocation until we're done changing it. We depend on
       * i_mutex to block other extend/truncate calls while we're
       * here.
       */
      down_write(&oi->ip_alloc_sem);

      if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
            /*
             * We can optimize small extends by keeping the inodes
             * inline data.
             */
            if (ocfs2_size_fits_inline_data(di_bh, new_i_size)) {
                  up_write(&oi->ip_alloc_sem);
                  goto out_update_size;
            }

            ret = ocfs2_convert_inline_data_to_extents(inode, di_bh);
            if (ret) {
                  up_write(&oi->ip_alloc_sem);

                  mlog_errno(ret);
                  goto out_unlock;
            }
      }

      if (!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
            ret = ocfs2_extend_no_holes(inode, new_i_size, new_i_size);

      up_write(&oi->ip_alloc_sem);

      if (ret < 0) {
            mlog_errno(ret);
            goto out_unlock;
      }

out_update_size:
      ret = ocfs2_simple_size_update(inode, di_bh, new_i_size);
      if (ret < 0)
            mlog_errno(ret);

out_unlock:
      if (data_locked)
            ocfs2_data_unlock(inode, 1);

out:
      return ret;
}

int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
{
      int status = 0, size_change;
      struct inode *inode = dentry->d_inode;
      struct super_block *sb = inode->i_sb;
      struct ocfs2_super *osb = OCFS2_SB(sb);
      struct buffer_head *bh = NULL;
      handle_t *handle = NULL;

      mlog_entry("(0x%p, '%.*s')\n", dentry,
                 dentry->d_name.len, dentry->d_name.name);

      if (attr->ia_valid & ATTR_MODE)
            mlog(0, "mode change: %d\n", attr->ia_mode);
      if (attr->ia_valid & ATTR_UID)
            mlog(0, "uid change: %d\n", attr->ia_uid);
      if (attr->ia_valid & ATTR_GID)
            mlog(0, "gid change: %d\n", attr->ia_gid);
      if (attr->ia_valid & ATTR_SIZE)
            mlog(0, "size change...\n");
      if (attr->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_CTIME))
            mlog(0, "time change...\n");

#define OCFS2_VALID_ATTRS (ATTR_ATIME | ATTR_MTIME | ATTR_CTIME | ATTR_SIZE \
                     | ATTR_GID | ATTR_UID | ATTR_MODE)
      if (!(attr->ia_valid & OCFS2_VALID_ATTRS)) {
            mlog(0, "can't handle attrs: 0x%x\n", attr->ia_valid);
            return 0;
      }

      status = inode_change_ok(inode, attr);
      if (status)
            return status;

      size_change = S_ISREG(inode->i_mode) && attr->ia_valid & ATTR_SIZE;
      if (size_change) {
            status = ocfs2_rw_lock(inode, 1);
            if (status < 0) {
                  mlog_errno(status);
                  goto bail;
            }
      }

      status = ocfs2_meta_lock(inode, &bh, 1);
      if (status < 0) {
            if (status != -ENOENT)
                  mlog_errno(status);
            goto bail_unlock_rw;
      }

      if (size_change && attr->ia_size != i_size_read(inode)) {
            if (attr->ia_size > sb->s_maxbytes) {
                  status = -EFBIG;
                  goto bail_unlock;
            }

            if (i_size_read(inode) > attr->ia_size)
                  status = ocfs2_truncate_file(inode, bh, attr->ia_size);
            else
                  status = ocfs2_extend_file(inode, bh, attr->ia_size);
            if (status < 0) {
                  if (status != -ENOSPC)
                        mlog_errno(status);
                  status = -ENOSPC;
                  goto bail_unlock;
            }
      }

      handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
      if (IS_ERR(handle)) {
            status = PTR_ERR(handle);
            mlog_errno(status);
            goto bail_unlock;
      }

      /*
       * This will intentionally not wind up calling vmtruncate(),
       * since all the work for a size change has been done above.
       * Otherwise, we could get into problems with truncate as
       * ip_alloc_sem is used there to protect against i_size
       * changes.
       */
      status = inode_setattr(inode, attr);
      if (status < 0) {
            mlog_errno(status);
            goto bail_commit;
      }

      status = ocfs2_mark_inode_dirty(handle, inode, bh);
      if (status < 0)
            mlog_errno(status);

bail_commit:
      ocfs2_commit_trans(osb, handle);
bail_unlock:
      ocfs2_meta_unlock(inode, 1);
bail_unlock_rw:
      if (size_change)
            ocfs2_rw_unlock(inode, 1);
bail:
      if (bh)
            brelse(bh);

      mlog_exit(status);
      return status;
}

int ocfs2_getattr(struct vfsmount *mnt,
              struct dentry *dentry,
              struct kstat *stat)
{
      struct inode *inode = dentry->d_inode;
      struct super_block *sb = dentry->d_inode->i_sb;
      struct ocfs2_super *osb = sb->s_fs_info;
      int err;

      mlog_entry_void();

      err = ocfs2_inode_revalidate(dentry);
      if (err) {
            if (err != -ENOENT)
                  mlog_errno(err);
            goto bail;
      }

      generic_fillattr(inode, stat);

      /* We set the blksize from the cluster size for performance */
      stat->blksize = osb->s_clustersize;

bail:
      mlog_exit(err);

      return err;
}

int ocfs2_permission(struct inode *inode, int mask, struct nameidata *nd)
{
      int ret;

      mlog_entry_void();

      ret = ocfs2_meta_lock(inode, NULL, 0);
      if (ret) {
            if (ret != -ENOENT)
                  mlog_errno(ret);
            goto out;
      }

      ret = generic_permission(inode, mask, NULL);

      ocfs2_meta_unlock(inode, 0);
out:
      mlog_exit(ret);
      return ret;
}

static int __ocfs2_write_remove_suid(struct inode *inode,
                             struct buffer_head *bh)
{
      int ret;
      handle_t *handle;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
      struct ocfs2_dinode *di;

      mlog_entry("(Inode %llu, mode 0%o)\n",
               (unsigned long long)OCFS2_I(inode)->ip_blkno, inode->i_mode);

      handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
      if (handle == NULL) {
            ret = -ENOMEM;
            mlog_errno(ret);
            goto out;
      }

      ret = ocfs2_journal_access(handle, inode, bh,
                           OCFS2_JOURNAL_ACCESS_WRITE);
      if (ret < 0) {
            mlog_errno(ret);
            goto out_trans;
      }

      inode->i_mode &= ~S_ISUID;
      if ((inode->i_mode & S_ISGID) && (inode->i_mode & S_IXGRP))
            inode->i_mode &= ~S_ISGID;

      di = (struct ocfs2_dinode *) bh->b_data;
      di->i_mode = cpu_to_le16(inode->i_mode);

      ret = ocfs2_journal_dirty(handle, bh);
      if (ret < 0)
            mlog_errno(ret);

out_trans:
      ocfs2_commit_trans(osb, handle);
out:
      mlog_exit(ret);
      return ret;
}

/*
 * Will look for holes and unwritten extents in the range starting at
 * pos for count bytes (inclusive).
 */
static int ocfs2_check_range_for_holes(struct inode *inode, loff_t pos,
                               size_t count)
{
      int ret = 0;
      unsigned int extent_flags;
      u32 cpos, clusters, extent_len, phys_cpos;
      struct super_block *sb = inode->i_sb;

      cpos = pos >> OCFS2_SB(sb)->s_clustersize_bits;
      clusters = ocfs2_clusters_for_bytes(sb, pos + count) - cpos;

      while (clusters) {
            ret = ocfs2_get_clusters(inode, cpos, &phys_cpos, &extent_len,
                               &extent_flags);
            if (ret < 0) {
                  mlog_errno(ret);
                  goto out;
            }

            if (phys_cpos == 0 || (extent_flags & OCFS2_EXT_UNWRITTEN)) {
                  ret = 1;
                  break;
            }

            if (extent_len > clusters)
                  extent_len = clusters;

            clusters -= extent_len;
            cpos += extent_len;
      }
out:
      return ret;
}

static int ocfs2_write_remove_suid(struct inode *inode)
{
      int ret;
      struct buffer_head *bh = NULL;
      struct ocfs2_inode_info *oi = OCFS2_I(inode);

      ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
                         oi->ip_blkno, &bh, OCFS2_BH_CACHED, inode);
      if (ret < 0) {
            mlog_errno(ret);
            goto out;
      }

      ret =  __ocfs2_write_remove_suid(inode, bh);
out:
      brelse(bh);
      return ret;
}

/*
 * Allocate enough extents to cover the region starting at byte offset
 * start for len bytes. Existing extents are skipped, any extents
 * added are marked as "unwritten".
 */
static int ocfs2_allocate_unwritten_extents(struct inode *inode,
                                  u64 start, u64 len)
{
      int ret;
      u32 cpos, phys_cpos, clusters, alloc_size;
      u64 end = start + len;
      struct buffer_head *di_bh = NULL;

      if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
            ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
                               OCFS2_I(inode)->ip_blkno, &di_bh,
                               OCFS2_BH_CACHED, inode);
            if (ret) {
                  mlog_errno(ret);
                  goto out;
            }

            /*
             * Nothing to do if the requested reservation range
             * fits within the inode.
             */
            if (ocfs2_size_fits_inline_data(di_bh, end))
                  goto out;

            ret = ocfs2_convert_inline_data_to_extents(inode, di_bh);
            if (ret) {
                  mlog_errno(ret);
                  goto out;
            }
      }

      /*
       * We consider both start and len to be inclusive.
       */
      cpos = start >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;
      clusters = ocfs2_clusters_for_bytes(inode->i_sb, start + len);
      clusters -= cpos;

      while (clusters) {
            ret = ocfs2_get_clusters(inode, cpos, &phys_cpos,
                               &alloc_size, NULL);
            if (ret) {
                  mlog_errno(ret);
                  goto out;
            }

            /*
             * Hole or existing extent len can be arbitrary, so
             * cap it to our own allocation request.
             */
            if (alloc_size > clusters)
                  alloc_size = clusters;

            if (phys_cpos) {
                  /*
                   * We already have an allocation at this
                   * region so we can safely skip it.
                   */
                  goto next;
            }

            ret = __ocfs2_extend_allocation(inode, cpos, alloc_size, 1);
            if (ret) {
                  if (ret != -ENOSPC)
                        mlog_errno(ret);
                  goto out;
            }

next:
            cpos += alloc_size;
            clusters -= alloc_size;
      }

      ret = 0;
out:

      brelse(di_bh);
      return ret;
}

static int __ocfs2_remove_inode_range(struct inode *inode,
                              struct buffer_head *di_bh,
                              u32 cpos, u32 phys_cpos, u32 len,
                              struct ocfs2_cached_dealloc_ctxt *dealloc)
{
      int ret;
      u64 phys_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys_cpos);
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
      struct inode *tl_inode = osb->osb_tl_inode;
      handle_t *handle;
      struct ocfs2_alloc_context *meta_ac = NULL;
      struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;

      ret = ocfs2_lock_allocators(inode, di, 0, 1, NULL, &meta_ac);
      if (ret) {
            mlog_errno(ret);
            return ret;
      }

      mutex_lock(&tl_inode->i_mutex);

      if (ocfs2_truncate_log_needs_flush(osb)) {
            ret = __ocfs2_flush_truncate_log(osb);
            if (ret < 0) {
                  mlog_errno(ret);
                  goto out;
            }
      }

      handle = ocfs2_start_trans(osb, OCFS2_REMOVE_EXTENT_CREDITS);
      if (handle == NULL) {
            ret = -ENOMEM;
            mlog_errno(ret);
            goto out;
      }

      ret = ocfs2_journal_access(handle, inode, di_bh,
                           OCFS2_JOURNAL_ACCESS_WRITE);
      if (ret) {
            mlog_errno(ret);
            goto out;
      }

      ret = ocfs2_remove_extent(inode, di_bh, cpos, len, handle, meta_ac,
                          dealloc);
      if (ret) {
            mlog_errno(ret);
            goto out_commit;
      }

      OCFS2_I(inode)->ip_clusters -= len;
      di->i_clusters = cpu_to_le32(OCFS2_I(inode)->ip_clusters);

      ret = ocfs2_journal_dirty(handle, di_bh);
      if (ret) {
            mlog_errno(ret);
            goto out_commit;
      }

      ret = ocfs2_truncate_log_append(osb, handle, phys_blkno, len);
      if (ret)
            mlog_errno(ret);

out_commit:
      ocfs2_commit_trans(osb, handle);
out:
      mutex_unlock(&tl_inode->i_mutex);

      if (meta_ac)
            ocfs2_free_alloc_context(meta_ac);

      return ret;
}

/*
 * Truncate a byte range, avoiding pages within partial clusters. This
 * preserves those pages for the zeroing code to write to.
 */
static void ocfs2_truncate_cluster_pages(struct inode *inode, u64 byte_start,
                               u64 byte_len)
{
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
      loff_t start, end;
      struct address_space *mapping = inode->i_mapping;

      start = (loff_t)ocfs2_align_bytes_to_clusters(inode->i_sb, byte_start);
      end = byte_start + byte_len;
      end = end & ~(osb->s_clustersize - 1);

      if (start < end) {
            unmap_mapping_range(mapping, start, end - start, 0);
            truncate_inode_pages_range(mapping, start, end - 1);
      }
}

static int ocfs2_zero_partial_clusters(struct inode *inode,
                               u64 start, u64 len)
{
      int ret = 0;
      u64 tmpend, end = start + len;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
      unsigned int csize = osb->s_clustersize;
      handle_t *handle;

      /*
       * The "start" and "end" values are NOT necessarily part of
       * the range whose allocation is being deleted. Rather, this
       * is what the user passed in with the request. We must zero
       * partial clusters here. There's no need to worry about
       * physical allocation - the zeroing code knows to skip holes.
       */
      mlog(0, "byte start: %llu, end: %llu\n",
           (unsigned long long)start, (unsigned long long)end);

      /*
       * If both edges are on a cluster boundary then there's no
       * zeroing required as the region is part of the allocation to
       * be truncated.
       */
      if ((start & (csize - 1)) == 0 && (end & (csize - 1)) == 0)
            goto out;

      handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
      if (handle == NULL) {
            ret = -ENOMEM;
            mlog_errno(ret);
            goto out;
      }

      /*
       * We want to get the byte offset of the end of the 1st cluster.
       */
      tmpend = (u64)osb->s_clustersize + (start & ~(osb->s_clustersize - 1));
      if (tmpend > end)
            tmpend = end;

      mlog(0, "1st range: start: %llu, tmpend: %llu\n",
           (unsigned long long)start, (unsigned long long)tmpend);

      ret = ocfs2_zero_range_for_truncate(inode, handle, start, tmpend);
      if (ret)
            mlog_errno(ret);

      if (tmpend < end) {
            /*
             * This may make start and end equal, but the zeroing
             * code will skip any work in that case so there's no
             * need to catch it up here.
             */
            start = end & ~(osb->s_clustersize - 1);

            mlog(0, "2nd range: start: %llu, end: %llu\n",
                 (unsigned long long)start, (unsigned long long)end);

            ret = ocfs2_zero_range_for_truncate(inode, handle, start, end);
            if (ret)
                  mlog_errno(ret);
      }

      ocfs2_commit_trans(osb, handle);
out:
      return ret;
}

static int ocfs2_remove_inode_range(struct inode *inode,
                            struct buffer_head *di_bh, u64 byte_start,
                            u64 byte_len)
{
      int ret = 0;
      u32 trunc_start, trunc_len, cpos, phys_cpos, alloc_size;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
      struct ocfs2_cached_dealloc_ctxt dealloc;
      struct address_space *mapping = inode->i_mapping;

      ocfs2_init_dealloc_ctxt(&dealloc);

      if (byte_len == 0)
            return 0;

      if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
            ret = ocfs2_truncate_inline(inode, di_bh, byte_start,
                                  byte_start + byte_len, 0);
            if (ret) {
                  mlog_errno(ret);
                  goto out;
            }
            /*
             * There's no need to get fancy with the page cache
             * truncate of an inline-data inode. We're talking
             * about less than a page here, which will be cached
             * in the dinode buffer anyway.
             */
            unmap_mapping_range(mapping, 0, 0, 0);
            truncate_inode_pages(mapping, 0);
            goto out;
      }

      trunc_start = ocfs2_clusters_for_bytes(osb->sb, byte_start);
      trunc_len = (byte_start + byte_len) >> osb->s_clustersize_bits;
      if (trunc_len >= trunc_start)
            trunc_len -= trunc_start;
      else
            trunc_len = 0;

      mlog(0, "Inode: %llu, start: %llu, len: %llu, cstart: %u, clen: %u\n",
           (unsigned long long)OCFS2_I(inode)->ip_blkno,
           (unsigned long long)byte_start,
           (unsigned long long)byte_len, trunc_start, trunc_len);

      ret = ocfs2_zero_partial_clusters(inode, byte_start, byte_len);
      if (ret) {
            mlog_errno(ret);
            goto out;
      }

      cpos = trunc_start;
      while (trunc_len) {
            ret = ocfs2_get_clusters(inode, cpos, &phys_cpos,
                               &alloc_size, NULL);
            if (ret) {
                  mlog_errno(ret);
                  goto out;
            }

            if (alloc_size > trunc_len)
                  alloc_size = trunc_len;

            /* Only do work for non-holes */
            if (phys_cpos != 0) {
                  ret = __ocfs2_remove_inode_range(inode, di_bh, cpos,
                                           phys_cpos, alloc_size,
                                           &dealloc);
                  if (ret) {
                        mlog_errno(ret);
                        goto out;
                  }
            }

            cpos += alloc_size;
            trunc_len -= alloc_size;
      }

      ocfs2_truncate_cluster_pages(inode, byte_start, byte_len);

out:
      ocfs2_schedule_truncate_log_flush(osb, 1);
      ocfs2_run_deallocs(osb, &dealloc);

      return ret;
}

/*
 * Parts of this function taken from xfs_change_file_space()
 */
static int __ocfs2_change_file_space(struct file *file, struct inode *inode,
                             loff_t f_pos, unsigned int cmd,
                             struct ocfs2_space_resv *sr,
                             int change_size)
{
      int ret;
      s64 llen;
      loff_t size;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
      struct buffer_head *di_bh = NULL;
      handle_t *handle;
      unsigned long long max_off = inode->i_sb->s_maxbytes;

      if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
            return -EROFS;

      mutex_lock(&inode->i_mutex);

      /*
       * This prevents concurrent writes on other nodes
       */
      ret = ocfs2_rw_lock(inode, 1);
      if (ret) {
            mlog_errno(ret);
            goto out;
      }

      ret = ocfs2_meta_lock(inode, &di_bh, 1);
      if (ret) {
            mlog_errno(ret);
            goto out_rw_unlock;
      }

      if (inode->i_flags & (S_IMMUTABLE|S_APPEND)) {
            ret = -EPERM;
            goto out_meta_unlock;
      }

      switch (sr->l_whence) {
      case 0: /*SEEK_SET*/
            break;
      case 1: /*SEEK_CUR*/
            sr->l_start += f_pos;
            break;
      case 2: /*SEEK_END*/
            sr->l_start += i_size_read(inode);
            break;
      default:
            ret = -EINVAL;
            goto out_meta_unlock;
      }
      sr->l_whence = 0;

      llen = sr->l_len > 0 ? sr->l_len - 1 : sr->l_len;

      if (sr->l_start < 0
          || sr->l_start > max_off
          || (sr->l_start + llen) < 0
          || (sr->l_start + llen) > max_off) {
            ret = -EINVAL;
            goto out_meta_unlock;
      }
      size = sr->l_start + sr->l_len;

      if (cmd == OCFS2_IOC_RESVSP || cmd == OCFS2_IOC_RESVSP64) {
            if (sr->l_len <= 0) {
                  ret = -EINVAL;
                  goto out_meta_unlock;
            }
      }

      if (file && should_remove_suid(file->f_path.dentry)) {
            ret = __ocfs2_write_remove_suid(inode, di_bh);
            if (ret) {
                  mlog_errno(ret);
                  goto out_meta_unlock;
            }
      }

      down_write(&OCFS2_I(inode)->ip_alloc_sem);
      switch (cmd) {
      case OCFS2_IOC_RESVSP:
      case OCFS2_IOC_RESVSP64:
            /*
             * This takes unsigned offsets, but the signed ones we
             * pass have been checked against overflow above.
             */
            ret = ocfs2_allocate_unwritten_extents(inode, sr->l_start,
                                           sr->l_len);
            break;
      case OCFS2_IOC_UNRESVSP:
      case OCFS2_IOC_UNRESVSP64:
            ret = ocfs2_remove_inode_range(inode, di_bh, sr->l_start,
                                     sr->l_len);
            break;
      default:
            ret = -EINVAL;
      }
      up_write(&OCFS2_I(inode)->ip_alloc_sem);
      if (ret) {
            mlog_errno(ret);
            goto out_meta_unlock;
      }

      /*
       * We update c/mtime for these changes
       */
      handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
      if (IS_ERR(handle)) {
            ret = PTR_ERR(handle);
            mlog_errno(ret);
            goto out_meta_unlock;
      }

      if (change_size && i_size_read(inode) < size)
            i_size_write(inode, size);

      inode->i_ctime = inode->i_mtime = CURRENT_TIME;
      ret = ocfs2_mark_inode_dirty(handle, inode, di_bh);
      if (ret < 0)
            mlog_errno(ret);

      ocfs2_commit_trans(osb, handle);

out_meta_unlock:
      brelse(di_bh);
      ocfs2_meta_unlock(inode, 1);
out_rw_unlock:
      ocfs2_rw_unlock(inode, 1);

      mutex_unlock(&inode->i_mutex);
out:
      return ret;
}

int ocfs2_change_file_space(struct file *file, unsigned int cmd,
                      struct ocfs2_space_resv *sr)
{
      struct inode *inode = file->f_path.dentry->d_inode;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);;

      if ((cmd == OCFS2_IOC_RESVSP || cmd == OCFS2_IOC_RESVSP64) &&
          !ocfs2_writes_unwritten_extents(osb))
            return -ENOTTY;
      else if ((cmd == OCFS2_IOC_UNRESVSP || cmd == OCFS2_IOC_UNRESVSP64) &&
             !ocfs2_sparse_alloc(osb))
            return -ENOTTY;

      if (!S_ISREG(inode->i_mode))
            return -EINVAL;

      if (!(file->f_mode & FMODE_WRITE))
            return -EBADF;

      return __ocfs2_change_file_space(file, inode, file->f_pos, cmd, sr, 0);
}

static long ocfs2_fallocate(struct inode *inode, int mode, loff_t offset,
                      loff_t len)
{
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
      struct ocfs2_space_resv sr;
      int change_size = 1;

      if (!ocfs2_writes_unwritten_extents(osb))
            return -EOPNOTSUPP;

      if (S_ISDIR(inode->i_mode))
            return -ENODEV;

      if (mode & FALLOC_FL_KEEP_SIZE)
            change_size = 0;

      sr.l_whence = 0;
      sr.l_start = (s64)offset;
      sr.l_len = (s64)len;

      return __ocfs2_change_file_space(NULL, inode, offset,
                               OCFS2_IOC_RESVSP64, &sr, change_size);
}

static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
                               loff_t *ppos,
                               size_t count,
                               int appending,
                               int *direct_io)
{
      int ret = 0, meta_level = 0;
      struct inode *inode = dentry->d_inode;
      loff_t saved_pos, end;

      /* 
       * We start with a read level meta lock and only jump to an ex
       * if we need to make modifications here.
       */
      for(;;) {
            ret = ocfs2_meta_lock(inode, NULL, meta_level);
            if (ret < 0) {
                  meta_level = -1;
                  mlog_errno(ret);
                  goto out;
            }

            /* Clear suid / sgid if necessary. We do this here
             * instead of later in the write path because
             * remove_suid() calls ->setattr without any hint that
             * we may have already done our cluster locking. Since
             * ocfs2_setattr() *must* take cluster locks to
             * proceeed, this will lead us to recursively lock the
             * inode. There's also the dinode i_size state which
             * can be lost via setattr during extending writes (we
             * set inode->i_size at the end of a write. */
            if (should_remove_suid(dentry)) {
                  if (meta_level == 0) {
                        ocfs2_meta_unlock(inode, meta_level);
                        meta_level = 1;
                        continue;
                  }

                  ret = ocfs2_write_remove_suid(inode);
                  if (ret < 0) {
                        mlog_errno(ret);
                        goto out_unlock;
                  }
            }

            /* work on a copy of ppos until we're sure that we won't have
             * to recalculate it due to relocking. */
            if (appending) {
                  saved_pos = i_size_read(inode);
                  mlog(0, "O_APPEND: inode->i_size=%llu\n", saved_pos);
            } else {
                  saved_pos = *ppos;
            }

            end = saved_pos + count;

            /*
             * Skip the O_DIRECT checks if we don't need
             * them.
             */
            if (!direct_io || !(*direct_io))
                  break;

            /*
             * There's no sane way to do direct writes to an inode
             * with inline data.
             */
            if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
                  *direct_io = 0;
                  break;
            }

            /*
             * Allowing concurrent direct writes means
             * i_size changes wouldn't be synchronized, so
             * one node could wind up truncating another
             * nodes writes.
             */
            if (end > i_size_read(inode)) {
                  *direct_io = 0;
                  break;
            }

            /*
             * We don't fill holes during direct io, so
             * check for them here. If any are found, the
             * caller will have to retake some cluster
             * locks and initiate the io as buffered.
             */
            ret = ocfs2_check_range_for_holes(inode, saved_pos, count);
            if (ret == 1) {
                  *direct_io = 0;
                  ret = 0;
            } else if (ret < 0)
                  mlog_errno(ret);
            break;
      }

      if (appending)
            *ppos = saved_pos;

out_unlock:
      ocfs2_meta_unlock(inode, meta_level);

out:
      return ret;
}

static ssize_t ocfs2_file_aio_write(struct kiocb *iocb,
                            const struct iovec *iov,
                            unsigned long nr_segs,
                            loff_t pos)
{
      int ret, direct_io, appending, rw_level, have_alloc_sem  = 0;
      int can_do_direct;
      ssize_t written = 0;
      size_t ocount;          /* original count */
      size_t count;           /* after file limit checks */
      loff_t old_size, *ppos = &iocb->ki_pos;
      u32 old_clusters;
      struct file *file = iocb->ki_filp;
      struct inode *inode = file->f_path.dentry->d_inode;
      struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

      mlog_entry("(0x%p, %u, '%.*s')\n", file,
               (unsigned int)nr_segs,
               file->f_path.dentry->d_name.len,
               file->f_path.dentry->d_name.name);

      if (iocb->ki_left == 0)
            return 0;

      vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);

      appending = file->f_flags & O_APPEND ? 1 : 0;
      direct_io = file->f_flags & O_DIRECT ? 1 : 0;

      mutex_lock(&inode->i_mutex);

relock:
      /* to match setattr's i_mutex -> i_alloc_sem -> rw_lock ordering */
      if (direct_io) {
            down_read(&inode->i_alloc_sem);
            have_alloc_sem = 1;
      }

      /* concurrent O_DIRECT writes are allowed */
      rw_level = !direct_io;
      ret = ocfs2_rw_lock(inode, rw_level);
      if (ret < 0) {
            mlog_errno(ret);
            goto out_sems;
      }

      can_do_direct = direct_io;
      ret = ocfs2_prepare_inode_for_write(file->f_path.dentry, ppos,
                                  iocb->ki_left, appending,
                                  &can_do_direct);
      if (ret < 0) {
            mlog_errno(ret);
            goto out;
      }

      /*
       * We can't complete the direct I/O as requested, fall back to
       * buffered I/O.
       */
      if (direct_io && !can_do_direct) {
            ocfs2_rw_unlock(inode, rw_level);
            up_read(&inode->i_alloc_sem);

            have_alloc_sem = 0;
            rw_level = -1;

            direct_io = 0;
            goto relock;
      }

      /*
       * To later detect whether a journal commit for sync writes is
       * necessary, we sample i_size, and cluster count here.
       */
      old_size = i_size_read(inode);
      old_clusters = OCFS2_I(inode)->ip_clusters;

      /* communicate with ocfs2_dio_end_io */
      ocfs2_iocb_set_rw_locked(iocb, rw_level);

      if (direct_io) {
            ret = generic_segment_checks(iov, &nr_segs, &ocount,
                                   VERIFY_READ);
            if (ret)
                  goto out_dio;

            ret = generic_write_checks(file, ppos, &count,
                                 S_ISBLK(inode->i_mode));
            if (ret)
                  goto out_dio;

            written = generic_file_direct_write(iocb, iov, &nr_segs, *ppos,
                                        ppos, count, ocount);
            if (written < 0) {
                  ret = written;
                  goto out_dio;
            }
      } else {
            written = generic_file_aio_write_nolock(iocb, iov, nr_segs,
                                          *ppos);
      }

out_dio:
      /* buffered aio wouldn't have proper lock coverage today */
      BUG_ON(ret == -EIOCBQUEUED && !(file->f_flags & O_DIRECT));

      if ((file->f_flags & O_SYNC && !direct_io) || IS_SYNC(inode)) {
            /*
             * The generic write paths have handled getting data
             * to disk, but since we don't make use of the dirty
             * inode list, a manual journal commit is necessary
             * here.
             */
            if (old_size != i_size_read(inode) ||
                old_clusters != OCFS2_I(inode)->ip_clusters) {
                  ret = journal_force_commit(osb->journal->j_journal);
                  if (ret < 0)
                        written = ret;
            }
      }

      /* 
       * deep in g_f_a_w_n()->ocfs2_direct_IO we pass in a ocfs2_dio_end_io
       * function pointer which is called when o_direct io completes so that
       * it can unlock our rw lock.  (it's the clustered equivalent of
       * i_alloc_sem; protects truncate from racing with pending ios).
       * Unfortunately there are error cases which call end_io and others
       * that don't.  so we don't have to unlock the rw_lock if either an
       * async dio is going to do it in the future or an end_io after an
       * error has already done it.
       */
      if (ret == -EIOCBQUEUED || !ocfs2_iocb_is_rw_locked(iocb)) {
            rw_level = -1;
            have_alloc_sem = 0;
      }

out:
      if (rw_level != -1)
            ocfs2_rw_unlock(inode, rw_level);

out_sems:
      if (have_alloc_sem)
            up_read(&inode->i_alloc_sem);

      mutex_unlock(&inode->i_mutex);

      mlog_exit(ret);
      return written ? written : ret;
}

static ssize_t ocfs2_file_splice_write(struct pipe_inode_info *pipe,
                               struct file *out,
                               loff_t *ppos,
                               size_t len,
                               unsigned int flags)
{
      int ret;
      struct inode *inode = out->f_path.dentry->d_inode;

      mlog_entry("(0x%p, 0x%p, %u, '%.*s')\n", out, pipe,
               (unsigned int)len,
               out->f_path.dentry->d_name.len,
               out->f_path.dentry->d_name.name);

      inode_double_lock(inode, pipe->inode);

      ret = ocfs2_rw_lock(inode, 1);
      if (ret < 0) {
            mlog_errno(ret);
            goto out;
      }

      ret = ocfs2_prepare_inode_for_write(out->f_path.dentry, ppos, len, 0,
                                  NULL);
      if (ret < 0) {
            mlog_errno(ret);
            goto out_unlock;
      }

      ret = generic_file_splice_write_nolock(pipe, out, ppos, len, flags);

out_unlock:
      ocfs2_rw_unlock(inode, 1);
out:
      inode_double_unlock(inode, pipe->inode);

      mlog_exit(ret);
      return ret;
}

static ssize_t ocfs2_file_splice_read(struct file *in,
                              loff_t *ppos,
                              struct pipe_inode_info *pipe,
                              size_t len,
                              unsigned int flags)
{
      int ret = 0;
      struct inode *inode = in->f_path.dentry->d_inode;

      mlog_entry("(0x%p, 0x%p, %u, '%.*s')\n", in, pipe,
               (unsigned int)len,
               in->f_path.dentry->d_name.len,
               in->f_path.dentry->d_name.name);

      /*
       * See the comment in ocfs2_file_aio_read()
       */
      ret = ocfs2_meta_lock(inode, NULL, 0);
      if (ret < 0) {
            mlog_errno(ret);
            goto bail;
      }
      ocfs2_meta_unlock(inode, 0);

      ret = generic_file_splice_read(in, ppos, pipe, len, flags);

bail:
      mlog_exit(ret);
      return ret;
}

static ssize_t ocfs2_file_aio_read(struct kiocb *iocb,
                           const struct iovec *iov,
                           unsigned long nr_segs,
                           loff_t pos)
{
      int ret = 0, rw_level = -1, have_alloc_sem = 0, lock_level = 0;
      struct file *filp = iocb->ki_filp;
      struct inode *inode = filp->f_path.dentry->d_inode;

      mlog_entry("(0x%p, %u, '%.*s')\n", filp,
               (unsigned int)nr_segs,
               filp->f_path.dentry->d_name.len,
               filp->f_path.dentry->d_name.name);

      if (!inode) {
            ret = -EINVAL;
            mlog_errno(ret);
            goto bail;
      }

      /* 
       * buffered reads protect themselves in ->readpage().  O_DIRECT reads
       * need locks to protect pending reads from racing with truncate.
       */
      if (filp->f_flags & O_DIRECT) {
            down_read(&inode->i_alloc_sem);
            have_alloc_sem = 1;

            ret = ocfs2_rw_lock(inode, 0);
            if (ret < 0) {
                  mlog_errno(ret);
                  goto bail;
            }
            rw_level = 0;
            /* communicate with ocfs2_dio_end_io */
            ocfs2_iocb_set_rw_locked(iocb, rw_level);
      }

      /*
       * We're fine letting folks race truncates and extending
       * writes with read across the cluster, just like they can
       * locally. Hence no rw_lock during read.
       * 
       * Take and drop the meta data lock to update inode fields
       * like i_size. This allows the checks down below
       * generic_file_aio_read() a chance of actually working. 
       */
      ret = ocfs2_meta_lock_atime(inode, filp->f_vfsmnt, &lock_level);
      if (ret < 0) {
            mlog_errno(ret);
            goto bail;
      }
      ocfs2_meta_unlock(inode, lock_level);

      ret = generic_file_aio_read(iocb, iov, nr_segs, iocb->ki_pos);
      if (ret == -EINVAL)
            mlog(ML_ERROR, "generic_file_aio_read returned -EINVAL\n");

      /* buffered aio wouldn't have proper lock coverage today */
      BUG_ON(ret == -EIOCBQUEUED && !(filp->f_flags & O_DIRECT));

      /* see ocfs2_file_aio_write */
      if (ret == -EIOCBQUEUED || !ocfs2_iocb_is_rw_locked(iocb)) {
            rw_level = -1;
            have_alloc_sem = 0;
      }

bail:
      if (have_alloc_sem)
            up_read(&inode->i_alloc_sem);
      if (rw_level != -1) 
            ocfs2_rw_unlock(inode, rw_level);
      mlog_exit(ret);

      return ret;
}

const struct inode_operations ocfs2_file_iops = {
      .setattr    = ocfs2_setattr,
      .getattr    = ocfs2_getattr,
      .permission = ocfs2_permission,
      .fallocate  = ocfs2_fallocate,
};

const struct inode_operations ocfs2_special_file_iops = {
      .setattr    = ocfs2_setattr,
      .getattr    = ocfs2_getattr,
      .permission = ocfs2_permission,
};

const struct file_operations ocfs2_fops = {
      .read       = do_sync_read,
      .write            = do_sync_write,
      .mmap       = ocfs2_mmap,
      .fsync            = ocfs2_sync_file,
      .release    = ocfs2_file_release,
      .open       = ocfs2_file_open,
      .aio_read   = ocfs2_file_aio_read,
      .aio_write  = ocfs2_file_aio_write,
      .ioctl            = ocfs2_ioctl,
#ifdef CONFIG_COMPAT
      .compat_ioctl   = ocfs2_compat_ioctl,
#endif
      .splice_read      = ocfs2_file_splice_read,
      .splice_write     = ocfs2_file_splice_write,
};

const struct file_operations ocfs2_dops = {
      .read       = generic_read_dir,
      .readdir    = ocfs2_readdir,
      .fsync            = ocfs2_sync_file,
      .ioctl            = ocfs2_ioctl,
#ifdef CONFIG_COMPAT
      .compat_ioctl   = ocfs2_compat_ioctl,
#endif
};

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